(1) Field of the Invention
The present invention relates to an improvement in an electrophotographic photosensitive material containing a tris-azo pigment in a photosensitive layer.
(2) Description of the Prior Art
It has been known from old that a dis-azo pigment is valuable as a photoconductive substance of an electrophotographic photosensitive material (see, for example, Japanese Patent Application Laid-Open Specification No. 37453/72). Furthermore, it has been known that a tris-azo pigment derived from triphenylmethane or an azoxy-bis(azobenzene) pigment can be used as a photoconductive pigment. In the field of electrophotographic reproduction, broadening of the sensitive wavelength region and increasing of the reproduction speed are always required, and development of a photoconductive pigment having a higher sensitivity and a broader sensitive wavelength region is always desired eagerly.